Frequency multiplying transformer



Aug; 1958 r P. P. BIRINGER 2,849,674

FREQUENCY MULTIPLYING TRANSFORMER Filed May 2, 1953 Sheets-Sheet 1 Fig.I

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United States Patent 6 FREQUENCY MULTIPLYING TRANSFORMER Paul PeterBiringer, Toronto, Ontario, Canada, assignor to The General EngineeringCompany Limited, Toronto, Ontario, Canada Application May 2, 1955,Serial No. 505,426

7 Claims. (Cl. 321-68) This invention relates to a frequency multiplyingtransformer havingpower factor correction.

This application is a continuation-in-part of my application SerialNumber 317,347, filed October 28, 1952,

assigned to the same assignee as the present application, now abandoned.

tive as a voltage sensitive amplifying device, the output voltage of thesecondary windings varies widely with primary voltage variations and thereactance of the high frequency winding is very high. Moreover, at highoperating flux densities of the core material at which the generation ofhigh harmonics begins, the current in the primary windings is distortedto such an extent that power factor correction in the primary windingsis not possible.

Prior frequency multiplying transformers do not demonstrate a powerfactor better than 0.5 regardless of the size of primary windingcondensers. Accordingly, former devices of low power factor feed higherharmonics into the power lines and demonstrate a large physical size forsmall power output. Such prior devices are therefore not of generalcommercial practicability.

The invention has for its main object, the provision of a frequencymultiplying transformer of satisfactory power factor correction forgeneral commercial use. I

Another object of the invention is to provide a frequency multiplyingtransformer embodying a compensating winding for each primary windingand magneti-cally coupled to the latter and a capacitance for eachcompensating winding adapted to compensate for current distortions inthe primary windings.

It is a further object of the invention to provide a frequencymultiplying transformer in which the power output can be controlled.

.It is a still further object of the invention to provide a frequencymultiplying transformer of a general form which may be adapted tomultiplying the frequency of any multiphase source of power.

With these and other objects in view, the invention generally relates toa, frequency multiplying transformer operative from a multi-phase sourceof electrical power of predetermined frequency and comprising incombination: a core providing a closed flux path for each phase of saidsource, a primary winding on each core connectable in phase to thesource, a secondary winding for each primary winding, and a compensatingwinding magnetically coupled to each primary winding and connected incircuit with a capacitance to compensate for distortions in the powersource.

The invention also concerns the'provision ofa control Winding for eachcore adapted to control the saturation ice 2 of the latter and therebythe .power output of the secondary winding.

The disclosure herein setting forth separate cores .providing a closedflux path for each phase of a power source should not be construed inany limiting sense as such cores may be partially combined physicallyand substantially the same operation results as set forth herein.

Other objects of the invention will be appreciated by a study of thefollowing specification taken in conjunction with the accompanyingdrawings.

.ln'the drawings:

Figure 1 is an electrical schematic of a simple form of frequencymultiplying transformer of the invention;

Figure 2 shows a .physical embodiment of the transformer of Figure 1;

Figure 3 is a plan view of one of the core structures of Figure 2;

Figure 4 is an electrical schematic of a further developed form of theinvention illustrating control windings for control of power output;

Figure 5 is an end View of a physical form of the transformer of Figure4;

Figure 6 is an elevation of the transformer of Figure 5;

Figure 7 is an electrical schematic of a frequency multiplyingtransformer of the invention as adapted to the multiplication offrequency of a twelve phase power source.

Figure 8 is a winding diagram for the windings of the transformer ofFigure 7; and

Figure 9 is an electrical schematic of a preferred method of poweroutput control operative from the power output of the transformer.

Referring to Figure 1, a frequency multiplying transformer it) for athree phase source is shown and comprises primary windings Ill, 12 and13 commonly connected at one end by the leads -14 to a floatingungrounded juncture point 14a and connected at their other ends by leads15, 16 and 17 to terminals 18, 19 and 2t) adapted to be connected to athree phase source of electrical power of predetermined frequency. As ina conventional frequency multiplying system, the secondary windings 21,22 and 23 are connected electrically in series by lines 24 and 25 andlines 26 and 27 to the load 28.

While attempts have been made to apply power factor correction directlyto the primary windings in prior systems, the invention provides amagnetically coupled compensating winding for each primary as designatedby numerals 29, 3t) and 31 commonly joined at one end by the loads 32and connected in delta arrangement with the capacitances 33, 34 and 35atthe other. The compensating windings are thus arranged so that thevoltages thereacross are distorted by the harmonics and contain all thedifferent harmonics and fundamentals except the third and multiples ofit. Accordingly, the capacitances provided across the terminals of thecompensating windings in appropriate phase connection will compensatefor all distortions in line current and effect satisfactory power factorcorrection in the ,power supply line.

The simplified form of the frequency multiplying transformer of'theinvention shown schematically in Figure 1 is illustrated in its physicalarrangement in Figure 2 where cores 36, 37 and 38 providing a completeor closed flux path for each phase of the power supplysource carrywindings 39, 40 and 41 embodying a primary, secondary and compensatingwinding in each case. Output is taken from the secondary windings bymeans of leads 26 and 27 and leads 15, 16 and I7 connect to the threephase source. Leads 42, 43 and 44 are connected to the condensers 33, 34and 35 (not shown). Connecting leads 14 join the lower ends of theprimary windings as shown in Figure 1. Each set of windings is placedupon a closed E-shaped laminated core 45 held in assembly by bolts 46.As shown in Figure 3, the Winding, for example, on the core 36, maycomprise the output winding or secondary winding 21 in the innermostposition; the input or primary winding 11 in an intermediate positionand the compensating winding 29 in the outermost position. Each windingis preferably formed of relatively flat copper tubing suitably boundwith insulation in a manner well known to skilled persons.

In many instances, it will be desired to provide a control over thepower output of the transformer construction shown in Figures 1 to 3.For this purpose, a control winding may be provided on each core asindicated in Figure 4 wherein like numerals indicate like components.Thus the control windings 47, 48 and 49 are provided for each of thewinding sets 39, 40 and 41 and are electrically connected in series tothe terminals 50 and 51 through a further series of control windings47a, 48a and 49a in reverse flux relation to the windings 39a, 40a and41a to thereby provide a means of controlling core saturation of thevarious core parts (not shown) supporting the windings. Morespecifically, a control winding is provided on each effectively separatecore. Each core is separated into two portions or parts so that twowinding sets are provided for each phase as 39, 39a for one phase; 40,40a for another phase; and 41, 41a for a third phase. Each winding setincludes a part of a control winding adapted to saturate its core partin a sense opposite to that effected by the other part of the controlwinding to cancel out frequency effects in the control windings. Asshown, the control windings are connected in series to terminals 50 and51 and thus would function as a frequency multiplying winding were thecancelling erect of the reverse winding parts not provided.

In general, the control windings for each phase are distributed over twocore parts adapted to be saturated oppositely by virtue of a reverseconnection of one halfsection of the control winding.

Accordingly, the direct current controlled transformer in its physicalform as shown in Figure embodies an upper core part 39 and a lower corepart 39a for each phase supported by the longitudinal framing strips 52,53 and 54 and the panel terminal strip 55 bolted to the core laminationsand maintaining the cores in the stacked assembly 56 shown in Figure 6.The invention herein set forth is not limited in its application to themultiplication of three phase power but may be generally employed forthe general multiplication of multi-phase electrical power in which theoutput frequency may be the fundamental phase multiple of the basicpower source frequency.

In this connection, it is to be noted that it is not intended to limitthe invention to an output of single phase power for once the form ofthe transformer of the invention as set forth herein is appreciated,skilled persons may modify the secondary windings for multi-phase outputor may, for example, connect three single phase output transformers ofthe invention for three phase output of the secondaries with phase shiftprimary connections. Also, it is not intended that in referring to thenumber of phases of the power source that a limitation of conventionalpower line phase number is to be implied, for it may be ofadvantage touse a conventional phase multiplying device of well known constructionto multiply a three phase power source to a greater phase number, forexample, twelve phase.

In a simplified illustration of the invention as applied to a largernumber of phases, a twelve phase source of power derived from a phasemultiplying transformer delivering say twelve phase sixty cycle power,may be converted to single phase 720 cycle power by the form of theinvention illustrated in Figure 7.

The twelve phase frequency multiplying transformer shown in Figure 7 isof the same general form as that of Figure 4 having a core providing aclosed flux path for each phase, that is, the cores 57 to 68 (eachcomprising two core parts), each having a primary winding 69, 69a, asecondary or output winding '70, 70a, 21 compensating winding 71, 71a,and a control winding 72, 72a. To facilitate electrical connection andassembly of the various winding sets on their core parts 57 to 68a,certain of the windings may be reversed so that four types of windingsare employed wherein type 1 on core part 57 has all the windings woundin the same directionptype 2 on core part 57a has the control windingwound in the reverse direction; type 3 winding on core part 58, has thesecondary and control windings wound in the reverse direction and a type4 winding on core part 58a has the secondary wound in the reversedirection. The relation of the winding types to the core parts isindicated in the winding diagram of Figure 8 wherein the upper figure ineach block of the diagram indicates the type of winding for the corepart identified by the core number in the block.

The leads 73 of the various primary windings are connected to the seriesof terminals 74 adapted to be connected to a twelve-phase source ofpower of predetermined frequency. The secondary windings 70, 70a areconnected electrically in series across the load 75 through a condenser76. It is also preferred to connect a condenser 77 in parallel with theload. Either one or both of the condensers 76 and 77 effect cancellingof the high reactance of the high frequency secondary and are preferablytuned in resonance at a frequency of 720 cycles in a twelve phasecircuit having a sixty cycle power source. In this manner, the poweroutput is limited only by the resistive components of the circuit. Notethat as in the previous forms discussed, the compensating windings 71,71a are connected commonly to the line 78 at one end and are connectedin circuit relation with their various condensers 79 at the other endsthereof to provide compensation for all distortions in line current inthe primary windings 69, 69a. As in the case of the form of transformershown in Figure 4, the control windings 72 are connected for currentflow in one direction in the upper set of core parts 57 to 63 and forcurrent flow in the opposite direction relative to the lower sets ofcore parts 57a to 68a to cancel out unwanted alternating currentcomponents in the control windings. Accordingly, a D. C. voltage appliedat terminals 80 and 81 will effect a core saturation power outputcontrol.

A useful method of obtaining direct current power for saturation controlpurposes is indicated in Figure 9 wherein the output or secondarywindings 70, 70a have connected in parallel with a portion thereof, thevariable transformer 82 connecting to a conventional stepdowntransformer and voltage regulator device 83, the output winding 84 ofwhich connects to the full wave rectifying circuit 85 havingconventional dry plate rectifying devices 86 therein and delivering afull wave rectified output by lines 87 and 88 to the terminals 80 and 81of control windings 72, 72a. By manual variation of the variabletransformer 82, the direct current power applied to the control windings72 may be varied to provide a close control over the saturation of thevarious core parts and the output of the transformer shown in Figure 7.The same control arrangement can be employed for the transformer formillustrated in Figure 4. The control has been shown to be effective asfor example in controlling asram It will be apparent that a wide rangeof output frequency and phase number is available for the design of afrequency multiplying transformer of the invention having regard toconventional phase multiplication of line power and the art ofmultiphase winding connections as applied to the teachings herein.

What I claim as my invention is:

l. A frequency multiplying transformer connectable to a multi-phasesource of electrical power of predetermined frequency and adapted toconvert said power to power of greater frequency with power factorcorrection and comprising in combination: a core providing a closed fluxpath for each phase of said source; a primary winding on each closedflux path of said core and connectable to said source; a secondarywinding on each closed flux path of said core; means connecting saidsecondary windings electrically in series for each power phaseobtainable from said secondary windings; a compensating windingmagnetically coupled to each primary winding; a Capacitance for saidcompensating windings; means electrically connecting said compensatingwindings and capacitances therefor to compensate for current distortionsin said primary windings; a control winding on each closed flux path ofsaid core for controlling saturation thereof; and means for applyingdirect current to said control windings for controlling the power outputof said secondary windings.

2. A frequency multiplying transformer connectable to a multi-phasesource of electrical power of predetermined frequency and adapted toconvert said power to power of greater frequency with power factorcorrection and comprising in combination: a core providing a closed fluxpath for each phase of said source; a primary winding on each closedflux path of said core and connectable to said source; a secondarywinding on each closed flux path of said core; means connecting saidsecondary windings electrically in series for each power phaseobtainable from said secondary windings; a compensating windingmagnetically coupled to each primary winding; a capacitance for saidcompensating windings; means electrically connecting said compensatingwindings and capacitances therefor to compensate for current distortionsin said primary windings; a control winding on each closed flux path ofsaid core for controlling saturation thereof; means for applying directcurrent to said control windings; and means for adjusting the directcurrent power applied to said control windings to control the poweroutput of said secondary windings.

3. A frequency multiplying transformer connectable to a multi-phasesource of electrical power of predetermined frequency and adapted toconvert said power to power of greater frequency with power factorcorrection and comprising in combination: a core providing a closed fluxpath for each phase of said source; a primary winding on each closedflux path of said core and connectable to said source; a secondarywinding on each closed flux path of said core; means connecting saidsecondary'windings electrically in series for each power phaseobtainable from said secondary windings; a compensating windingmagnetically coupled to each primary winding; a capacitance for saidcompensating windings; means electrically connecting said compensatingwindings and capacitances therefor to compensate for current distortionsin said primary windings; a control winding on each closed flux path ofsaid core for controlling saturation thereof; means for applying directcurrent to said control windings for controlling the power output ofsaid secondary windings; a variable transformer energizable by saidsecondary windings; voltage rectifying means including a regulatingdevice connected to said variable transformer and providing therefrom acontrollable direct current source of power; and meanselectricallyconnecting said direct current source of power to saidcontrol windings.

4. A frequency multiplying transformer connectable to a multi-phasesource of electrical power of predetermined frequency and adapted toconvert said power to power of greater frequency with power factorcorrection and comprising in combination: a core providing a closed fluxpath for each phase of said source; a primary winding on each closedflux path of said core and connectable to said source; a secondarywinding on each closed flux path of said core; means connecting saidsecondary windings electrically in series for each power phaseobtainable from said secondary windings; a compensating windingmagnetically coupled to each primary winding; a capaci tance for saidcompensating windings; means electrically connecting said compensatingwindings and capacitances therefor to compensate for current distortionsin said primary windings; a control winding on each closed flux path ofsaid core for controlling saturation thereof; means for applying directcurrent to said control windings for controlling the power output ofsaid secondary windings; a variable transformer energizable by saidsecondary windings; full wave voltage rectifying means including aregulating device connected to said variable transformer and providingtherefrom an adjustable direct current source of power; and meanselectrically connecting said direct current source of power to saidcontrol windings.

5. A frequency multiplying transformer connectable to a multi-phasesource of electrical power of predetermined frequency and adapted toconvert said power to power of greater frequency with power factorcorrection and comprising in combination: a separate core providing aclosed flux path for each phase of said source; a primary winding oneach closed flux path of said core and connectable to said source; asecondary winding on each closed flux path of said core; meansconnecting said secondary windings electrically in series for each powerphase obtainable from said secondary windings; a compensating windingcoupled to each primary winding; a capacitance for said compensatingwindings; means electrically connecting said compensating windings andcapacitances therefor to compensate for current distortions in saidprimary windings; a control winding on each closed flux path of saidcore for controlling saturation thereof; means for applying directcurrent to said control winding for controlling the power output of saidsecondary windings; means for connecting said secondary windings to aload; and capacitance means for cancelling the high reactance of saidsecondary windings.

6. A frequency multiplying transformer connectable to a multi-phasesource of electrical power of predetermined frequency and adapted toconvert said power to power of greater frequency with power factorcorrection and comprising in combination: a core providing a closed fluxpath for each phase of said source; a primary winding on each closedflux path of said core and connectable to said source; a secondarywinding on each closed flux path of. said core; means connecting saidsecondary windings electrically in series for each power phaseobtainable from said secondary windings; a compensating windingmagnetically coupled to said primary windings; a capacitance for eachcompensating winding; means electrically connecting said compensatingwindings and capacitances therefor to compensate for current distortionsin said primary windings; a control winding on each closed flux path ofsaid core for controlling saturation thereof; means for applying directcurrent to said control windings to provide control over the poweroutput of said secondary windings; said saturable core portions eachbeing in the form of an individual core having a portion of each of saidwindings thereon; and structural means supporting said individual coresin stacked array.

7. A frequency multiplying transformer connectable to a multi-phasesource of electrical power of predetermined frequency and adapted toconvert said power to power of greater frequency and comprising incombination: a core providing a closed flux path for each phase of saidsource; a primary winding on each closed flux path of said core andconnectable to said source; a secondary winding on each closed flux pathof said core; means connecting said secondary windings electrically inseries providing a single power phase obtainable from said secondarywindings; a control winding on each closed flux path of said core forcontrolling saturation thereof; means for applying direct current tosaid control windings for controlling the power output of said secondarywindings; a variable transformer energizable by said secondary windings;voltage rectifying means including a regulating device connected to saidvariable transformer and providing therefrom a controllable directcurrent source of power; and means electrically connecting said directcurrent source of power to said control windings.

References Cited in the file of this patent UNITED STATES PATENTSSpinelli Oct. 26, 1915 Ohl July 20, 1926 Lindenblad J an. 6, 1931 HugeFeb. 26, 1946 Kramer Jan. 12, 1954 FOREIGN PATENTS Germany Feb. 8, 1939

